API logs expose cookies, proxy credentials, and request/response secrets

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### Is there already an issue for your problem?

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YES

### Environment

```markdown
- FlareSolverr version: master at 0f05ed8fc974b215c36892b5a30122e27fe3c671
- Last working FlareSolverr version: unknown
- Operating system: Ubuntu 24.04 (remote deployment inspection)
- Are you using Docker: yes
- FlareSolverr User-Agent (see log traces or / endpoint): not applicable
- Are you using a VPN: no
- Are you using a Proxy: yes
- URL to test this issue: any endpoint sending authenticated cookies or proxy credentials
```

### Description

## Description

The API controller logs the complete request payload at INFO level and the complete response object at DEBUG level. Those structures can contain cookies, headers, passwords, post data, proxy URLs and credentials, response HTML, screenshots, and CAPTCHA tokens. A default deployment can therefore persist secrets in service logs.

## Expected behaviour

Operational logs should retain useful metadata while masking authentication material and sensitive request and response fields.

## Proposed fix

Add a recursive redaction helper for known sensitive keys, use it for incoming request and debug response logs, and preserve only non-sensitive metadata. A focused test verifies that representative secrets do not appear in the logged output.

### Logged Error Messages

```text
No service failure is required; the exposure is visible in normal request logging when sensitive fields are supplied.
```

### Screenshots

_No response_

Start at the API controller's INFO request-payload and DEBUG response-object logging described in the issue. Identify the sensitive keys and logging paths, add the proposed recursive redaction helper and a focused test, then verify that representative cookies, credentials, tokens, and other secrets do not appear while useful metadata remains.

Written by the indexing model from the issue text.